Incremental dose dispenser

ABSTRACT

A dispenser is provided for use in conjunction with syringes and is capable of accurate, rapid dispensing of small incremental doses and rapid and convenient refilling of the syringe. The dispenser comprises an elongated plunger for engaging and advancing the piston of the syringe to expell liquid doses therefrom. The plunger is threaded along at least a portion of its longitudinal, peripheral surface. A drive wheel is provided for advancing the plunger; the drive wheel having its peripheral surface divided into alternate threaded sections and longitudinal separating grooves. The threaded sections engage the threaded portions of the plunger advancing the same to rapidly dispense the incremental doses. The longitudinal grooves provide a clearance between the plunger and drive wheel thereby leaving the plunger disengaged for rapid refilling of the syringe.

. United States Patent 1191 Luciano et al.

14 1 Feb. 5, 1974 INCREMENTAL DOSE DISPENSER [73] Assignee: OrthoPharmaceutical Corporation,

Raritan, NJ.

[22] Filed: July 28, 1972 [21] Appl. No.: 276,196

[52] US. Cl 222/390, 74/128, 128/218 R, 222/391 [51] Int. Cl A6lm 5/2258 Field of Search...222/390, 391, 128/218 R, 218 A;74/126, 128

[56] References Cited 7/1964 Mapel Primary Examiner-Robert B. ReevesAssistant ExaminerThomas E. Kocovsky Attorney, Agent, or Firm-JasonLipow et a1.

[5 7] ABSTRACT A dispenser is provided for use in conjunction withsyringes and is capable of accurate, rapid dispensing of smallincremental doses and rapid and convenient refilling of the syringe. Thedispenser comprises an elongated plunger for engaging and advancing thepiston of the syringe to expell liquiddoses therefrom. The plunger isthreaded along at least a portion of its longitudinal, peripheralsurface. A drive wheel is provided for advancing the plunger; the drivewheel having its peripheral surface divided into alternate threadedsections and longitudinal separating grooves. The threaded sectionsengage the threaded portions of the plunger advancing the same torapidly dispense the incremental doses..The longitudinal grooves providea clearance between the plunger and drive wheel ing'of the syringe.

6 Claims, 4 Drawing Figures PATENTEOFEB slam E ll 1 INCREMENTAL DOSEDISPENSER This invention concerns liquid dispensers and particularlythose designed to be used in conjunction with syringes and capable ofdispensing accurate, incremental doses, each of which is only a smallfraction of the total capacity of the syringe. Such dispensers areespecially useful in laboratory work where a task frequently involvesthe rapid and accurate dispensing of many small incremental doses of areagent from a storage supply such as a prefilled syringe. In such work,it is frequently necessary to refill the syringe after the supply isdepleted and then continue to dispense the small accurate doses.Heretofore, no device has been available to smoothly perform thetransition between accurate, rapid dispensing of small doses and rapidand convenient refilling of the syringe.

In accordance with this invention, a liquid dispenser is provided foruse with a syringe having a liquidcontaining cartridge, open at one end,and a piston, generally slidably mounted in the cartridge, for expellingthe liquid out of the open end. The opening is usually fitted with acannula for accurately directing the flow of liquid to the desireddelivering point.

The dispenser of this invention comprises a housing and, mounted thereonand in reciprocating relationship thereto, an elongated plunger havingmeans at one end for engaging the piston of the syringe so as to advanceit and expell liquid therefrom. The plunger is threaded along at least aportion of its elongated peripheral surface. A cylindrical drive wheel,for advancing the plunger, is rotatably mounted to the housing. Thedrive wheel is threaded along its peripheral surface, the threads beinginterrupted by'radially spaced grooves cut into the peripheral surfaceand extending parallel to the axis of the drive wheel. Thus, theperipheral surface presents a plurality of alternating threaded sectionsand separating grooves. The drive wheel is mounted on-the housing,relative to the plunger, so that itmay be rotated to, alternatively,bring the threaded sections and the separating grooves into registerwith the threaded portion of the plunger. Further, the threaded sectionof the drive wheel and the threaded portion of the plunger engage whenthey are in register are provided for rotating the drive wheel through apre-' selected degree of rotation, the degree of rotation, however,selected so asto always terminate with a groove of the drive wheel inregister with the threads of the plunger (i.e., with the plungerdisengaged from the drive wheel by virtue of the clearance between thethreaded section of the plunger and the drive wheel).

In operation, as the drivewheel passes through a degree of rotationcorresponding to one threaded section in engagement with the plunger,the plunger will advance reciprocally a discrete incremental distance.This, in turn, will advance the piston of the syringe the Sameincremental distance and hence-dispense a controlled incremental dose ofliquid. By preselecting the degree of rotation of the drive wheel tocorrespond to any number of threaded sections, the plunger may beadvanced a desired multiple of increments and a dose, of the sizecorresponding to multiple increments, may be delivered.

In accordance with this invention, the preselected degree of rotationalways terminates with the threaded portion of the plunger in registerwith a groove on the drive wheel. Thus, by virtue of the clearancebetween the groove and the plunger, the dispenser is always in adisengaged state after each dose has been dispensed, i.e., the plungerfree to move, reciprocally to any extent with-out having to actuate therotating mechanism. A user may, therefore, dispense any number of doses,each of a preselected size, and then, after a series of dose dispensing,the usermay freely move the plunger, so as to fill or empty the syringe.

A better understanding of the inventionwill be had by referring to theappended drawings, illustrating a specific embodiment of the invention,as taken together with the following description.

Referring now to the drawings:

FIG. 1 is a perspective view of a dispenser embodying this invention asused in conjunction with a syringe;

FIG. 2 is a longitudinal, partial section taken along line 2-2 of FIG.1;

FIG. 3 is a transverse, partial section taken along line 3-3 of FIG. 2;and I FIG. 4 is an exploded, perspective view of a portion of thedispenser and syringe shown in FIG. 1.

As best shown in FIG. 1, a dispenser 10 is provided with a gun-shapedhousing 12 having an arm 14 for supporting'a syringe 16. The syringecomprises a cartridge 18 for containing a supply of a liquid, thecartridge terminating in an opening 20 having, fitted therein, a cannula22 for accurately directing the flow of liquid to the desired deliverypoint. Externally accessible, depressible means, illustrated in thedrawing, by a trigger 24, is provided for actuating the dispenser, and aselection wheel 26 is provided for selecting the size of the dosecorresponding to one full actuation, i.e., one full depression of thetrigger. The housing 12 is also provided with an arm 28 for supporting aplunger (not shown in FIG. 1) which engages the piston'of the syringe(also not shown in FIG. 1). The arm 28 has a slot 30 runninglongitudinally therewith through which a projection 32, integral withthe plunger, extends for manually repositioning the plunger. Inoperation, the size of a given doseis preselected, by rotating theselection wheel. The trigger is then depressed, activating the dispenserand advancing the plunger and the piston of the syringe so as todispense the preselected dose.

Referring now to FIGS. 2, 3, and 4, the plunger 34 as illustrated,reciprocally mounted to the housing 12, and provided with means forengaging the piston 36, said piston being slidably mounted in thecartridge 18 of the syringe 16 so as to be capable of advancing andexpelling liquid contained within the cartridge through the cannula 22.The engagement means shown comprise a small projection 38 extendingcollinearly from the end of the plunger and having a circumferentialbead 40 for snap-fitting into a corresponding bore 42 provided in oneend of the piston 36.

The plunger comprises an elongated member having threads 44 on a portionof its longitudinal peripheral surface. As best shown in FIGS. 2 and 3,surfaces of the plunger 46, and 48 are preferably flattened andcontained against corresponding surfaces 46',and 48 of the housing toprevent rotation of the plunger in operation and to limit movement ofthe plunger to reciprocal motion. Thus, as assembled, the plunger, thepiston and the syringe cartridge are each co-aligned and collinear withthe reciprocating motion of the plunger.

A drive wheel 50, forfadvancing the plunger is rotatably mounted to thehousing and is provided with threads 52, cut into its peripheralsurface. These threads are interrupted by radially spaced grooves 54,extending parallel to the axis of the drive wheel. Thus, as best viewedin cross-section in FIG. 3, and in perspective in FIG. 4, the peripheralsurface of the drive wheel displays a plurality of radially spaced,alternating threaded and grooved sections.

The drive wheel is rotatably mounted in the housing so that the threadedsections 52 may be rotated into register and engage the threaded portionof the plunger. In this position of engagement, the plunger can only beadvanced by rotation of the drive wheel, the extent of the advance beingdetermined by the degree of rotation of the drive wheel and the pitchlength of the threads. For example, when the threads of the drive wheelhave a pitch length equal the the threads of the plunger, the plungerwill move reciprocally one pitch length per thread-engaged revolution.On the other hand, if the wheel is rotated through only one fifth of therevolution, the plunger will advance a distance equal to 0.2 times thepitch length. For the specific embodiment illustrated in the drawings,the drive wheel comprises five equal, radially spaced, grooves 54. Thepitch length is chosen so that rotation of the drive wheel through onethreaded section will advance the plunger and hence, the engaged pistonof the syringe, a distance equivalent to one incremental dose. Arotation of the drive wheel through two threaded sections will deliver adose equal to two increments. Similarly, a three, four and fiveincremental dose may be delivered by corresponding rotation of the drivewheel through a corresponding number of threaded sections. As will bemore fully described below, means are provided for actuating the deviceto rotate the drive wheel through a pre-selected number of threadsections per actuator and hence deliver a preselected dose size peractuation.

Irrespective of the number of threaded sections selected'to be rotatedin engagement with the plunger per actuation, at the end of eachactuation, the drive wheel rotation terminates with a longitudinalgroove in register with the threads of the plunger. As best viewed inFIG. 3, the longitudinal grooves are cut to a depth sufficient toprovide a clearance 56 between the threads of the plunger and the drivewheel when the grooves and the plunger are in register. By virtue ofthis clearance, the plunger is then free to move reciprocally afterevery rotation. Thus, in accordance with'this invention, the drive wheelmay be actuated repeatedly to deliver repeated doses, each ofapre-selected size. At the end of each delivery, the plunger iscompletely disengaged from the drive wheel and may be manuallyrepositioned by gripping the projection 32 and sliding the plunger.Thus, for example, at any time the syringe may be refilled and theplunger will be immediately ready to deliver further incremental doses.To insure that the threads will mesh, as the threaded section of thewheel is rotated into engagement with the threads of the plunger,bearing plate 58 is provided, urged into contact with the plunger by aspring 60.

As mentioned above, means are provided for actuating the device byrotating the drive wheel through a preselected degree of rotation. Suchmeans comprise the trigger 24, for depressing once per actuation and aspring 62, to thereafter return the trigger to its original, undepressedposition. Translating means are provided for translating thereciprocating motion of the depressing trigger into a rotary motion forrotating the drive wheel. The translating means comprise a cam pin 64mounted to the trigger and hence adopting the reciprocating motion ofthe trigger when depressed. The cam pin cooperates with a cam barrel 66,rotatably mounted to the housing and having cut therein, a helicalcamway 68 in which the cam pin travels reciprocally and, by cam action,rotates the cam barrel. Transmitting means are provided for transmittingthe rotary motion of the cam barrel to the drive wheel. Thesetransmitting means comprise, in serial, coaxial alignment: a cam barreldrive shaft 70; integral therewith, the driving element 72 of atwo-element ratchet; and, integral with the drive wheel 50, the drivenelement 74 of the ratchet. Thecam barrel, the cam barrel drive shaft andthe driving element of the ratchet all rotate when the trigger is eitherdepressed or repositioned by the action of spring 62. The two elementsof the ratchet co-engage by means of teeth 75, slanted so as to causethe driving element, when rotated, as when the trigger is depressed, torotate the driven element 74 in a direction corresponding to theadvancement of the plunger. On the other hand, when the driving elementis rotating in the opposite direction, as when the trigger isrepositioned by the action of the spring 62, the teeth 75 will slip pasteach other and the driven element 74 will not rotate. To allow for suchslippage, the driving element 72 of the ratchet is mounted on the end ofthe cam barrel drive shaft 70 so as to be limitedly slidable, with aspring 76 provided to supply sufficient tension to urge the teeth of thetwo elements to co-engage when the trigger is depressed, the spring alsobeing sufficiently yieldable to allow the driving element to slide backon the cam barrel drive shaft when the trigger returns to theundepressed position by the action of the spring 62.

As described above, the size of the dose delivered per actuation of thedevice, i. e., per depression of the trigger, is determined by thedegree of rotation of the drive wheel. Stated in other words, the dosesize is determined by the number of threaded sections of the drive wheelrotated in engagement with the thread plunger. Because of the coaxialalignment of the cam barrel, cam barrel drive shaft, ratchet and drivewheel, the degree of rotationof the drive wheel is determined by thedegree of one full rotation of the cam barrel; rotation of 1 the cambarrel in the advancing direction of the v plunger will produce a fullrotation of the drive wheel.

The degree of rotation of the cam barrel, in turn, is a function of theextent of travel of the cam pin in the cam way. In the embodimentillustrated in the drawings, means are provided for setting the travelof the cam pin to a preselected limit and hence preselecting the size ofthe dose per actuation. These means comprise a limiting pin 78 mountedon the trigger and projecting therefrom in the direction of triggertravel. The limiting pin cooperates with a selection barrel 80,rotatably mounted on the housing and having a face 82 opposing, andspaced apart from, the limiting pin. The selection barrel is provided,on the face of the barrel opposing the limiting pin, with a series ofradially spaced bores 84 of varying depth. Each of the bores may beselectively brought into register for receiving the limiting pin byrotating the selection barrel.

When any one of the bores is brought into register, the extent of travelof the trigger when fully depressed is limited to the distance betweenthe projecting end of the limiting pin and the bottom of the bore.Accordingly, by rotating the selection barrel into register with aselected bore, the degree of travel of the trigger, the degree ofrotation of the drive wheel and hence, the dose size may be selected. Inthe embodiment lllGS- trated in the drawings, the depth of theshallowest bore is sized to correspond to a degree of rotation of thedrive wheel equal to rotating the drive wheel through one threadedsection 52 from one longitudinal groove 54 to the next. Accordingly,when selectively registering the shallowest bore, the device willdispense a dose of an'incremental size equivalent to the plunger andpiston advancement resulting from rotating the one threaded section 52of the drive wheel in engagement with the threads of the plunger. Thedeepest bore corresponds to rotating the drive wheel through one fullrotation, i. e., five threaded sections 52, and hence by registeringthis-bore, the device will dispense a five-fold incremental dose. Statedgenerally, the selection barrel is provided with a bore of a depthlimiting the degree of trigger travel, to that corresponding to arotation of the drive wheel through a preselected number of threadssections on the drive wheel.

it will be apparent to one skilled in the art that the actual volume ofa single incremental dosage, i. e., a dosage equivalen't'to rotating thedrive wheel through one threaded section, is a function of such factorsas the pitch length selected for the threads, the number of threadedsections per revolution, and the volume displaced in the syringe by alimited length of piston travel. The device may be designed to deliveryany of a wide range of incremental dose sizes. For example, a devicedispensing a one micro-litre incremental dose may be designed by using asyringe having an inside diameter of /a-in. in combination with a drivewheel, threaded with five sections'and using'a pitch length of 0.025inches for both the threads on the drive wheel and the threads on theplunger. With this combination,

the device is capable of alternatively delivering doses of l, 2, 3, 4 or5 microlitres per actuation.

The dispenser of this invention may be made from various materials ofconstruction known to those skilled in the art and limited only by sucheconomic considerations as the cost of raw material, the ease ofmanufacture, and the durability of parts, when taking into considerationthe repeated usageof the dispenser. For example, a preferred method ofmanufacture is the well-known injection molding technique using variousmaterials and composites such as ABS (acrylonitrude, butadiene andstyrene), Noryl (polycarbonate), or reinforced nylon. Metals, capable ofbeing machined,

l. A dispenser for delivering a controlled dose of liquid from a syringehaving a liquid containing cartridge open at one end and a piston forexpelling the liquid through the open end of the cartridge, saiddispenser 5 comprising:

a. a housing;

b. an elongated plunger, reciprocally mounted on said housing, havingmeans at one end for engaging said piston, and being threadedalong atleast a portion of its longitudinal peripheral surface;

c. a cylindrical drive Wheel for advancing said plunger, rotatablymounted to said housing, said drive wheel being threaded along itsperipheral surface, said threads being interrupted by radially spacedgrooves cut into the peripheral surface and extending parallel to theaxis of said drive wheel and separating said threads into radiallyspaced threaded sections;

d. said drive wheel being mounted, relative to said plunger, so that itmay be rotated to alternatively bring said threaded sections and saidgrooves into register with said plunger, the threaded sections whenbrought into register with said plunger, .engaging the threads of saidplunger and the grooves when brought into register with said plungerproviding a clearance. between said drive wheel and said plunger; and

e. actuating means for rotating said drive wheel through at least onethreaded section and from registry with one separating groove toregistry with any separating groove, thereby advancing said plunger andsaid piston, said rotation ending with said plunger disengaged from saiddrive wheel.

2. The dispenser of claim 1 provided with preselecting means forselecting the number of threaded sections through which said actuatingmeans will rotate said drive wheel per actuation.

3. The dispenser of claim 2 wherein said preselecting means comprise:

a limiting pin mounted on said depressible element and projectingtherefrom in the direction 'of depression;

a cylindrical section barrel, rotatably mounted on said housing, andhaving a face opposing and spaced apart from said limiting pin whensaid' depressible element is in the undepressed state;

said opposing face provided with a plurality of radially spaced bores;

said selection barrel being mounted with respect to said limitingpinsothat each of said, bores may be selectively brought into register forreceiving said limiting pi'n by rotating said selection barrel, wherebythe degree of reciprocal travel of said depressible element'is limitedby the depth of each bore, each bore having a depth limiting the degreeof said depressible element travel to corresponding to a rotation ofsaid drive wheel through a preselected number of threaded sections.

.4. The dispenser of claim 1 wherein said actuating means comprise:

a depressible element, reciprocally mounted to said housing;

translating means for translating the reciprocating motion of saiddepressible means to rotary motion; and

driving means for transmitting said rotary motion to said drive wheel.

a cam barrel drive shaft, integral with said cam barrel;

a driving element of a two-part ratchet, integral with said drive shaft;and

the driven element of the two-part ratchet, integral with said drivewheel;

said cam barrel, said drive shaft, said driving element, said drivenelement, and said drive wheel all being coaxially aligned.

1. A dispenser for delivering a controlled dose of liquid from a syringehaving a liquid containing cartridge open at one end and a piston forexpelling the liquid through the open end of the cartridge, saiddispenser comprising: a. a housing; b. an elongated plunger,reciprocally mounted on said housing, having means at one end forengaging said piston, and being threaded along at least a portion of itslongitudinal peripheral surface; c. a cylindrical drive wheel foradvancing said plunger, rotatably mounted to said housing, said drivewheel being threaded along its peripheral surface, said threads beinginterrupted by radially spaced grooves cut into the peripheral surfaceand extending parallel to the axis of said drive wheel and separatingsaid threads into radially spaced threaded sections; d. said drive wheelbeing mounted, relative to said plunger, so that it may be rotated toalternatively bRing said threaded sections and said grooves intoregister with said plunger, the threaded sections when brought intoregister with said plunger, engaging the threads of said plunger and thegrooves when brought into register with said plunger providing aclearance between said drive wheel and said plunger; and e. actuatingmeans for rotating said drive wheel through at least one threadedsection and from registry with one separating groove to registry withany separating groove, thereby advancing said plunger and said piston,said rotation ending with said plunger disengaged from said drive wheel.2. The dispenser of claim 1 provided with preselecting means forselecting the number of threaded sections through which said actuatingmeans will rotate said drive wheel per actuation.
 3. The dispenser ofclaim 2 wherein said preselecting means comprise: a limiting pin mountedon said depressible element and projecting therefrom in the direction ofdepression; a cylindrical section barrel, rotatably mounted on saidhousing, and having a face opposing and spaced apart from said limitingpin when said depressible element is in the undepressed state; saidopposing face provided with a plurality of radially spaced bores; saidselection barrel being mounted with respect to said limiting pin so thateach of said bores may be selectively brought into register forreceiving said limiting pin by rotating said selection barrel, wherebythe degree of reciprocal travel of said depressible element is limitedby the depth of each bore, each bore having a depth limiting the degreeof said depressible element travel to corresponding to a rotation ofsaid drive wheel through a preselected number of threaded sections. 4.The dispenser of claim 1 wherein said actuating means comprise: adepressible element, reciprocally mounted to said housing; translatingmeans for translating the reciprocating motion of said depressible meansto rotary motion; and driving means for transmitting said rotary motionto said drive wheel.
 5. The dispenser of claim 4 wherein saidtranslating means comprise: a cam pin mounted on said depressibleelement and adopting the reciprocal motion thereof; a cam barrel,rotatably mounted on said housing and having a helical cam way cuttherein for receiving said cam pin and, by cam action, converting thereciprocating motion of said cam pin into rotary motion of said cambarrel.
 6. The dispenser of claim 5 wherein the transmitting meanscomprise: a cam barrel drive shaft, integral with said cam barrel; adriving element of a two-part ratchet, integral with said drive shaft;and the driven element of the two-part ratchet, integral with said drivewheel; said cam barrel, said drive shaft, said driving element, saiddriven element, and said drive wheel all being coaxially aligned.